My senior year of high school, I worked as a server on weekend mornings at a small diner in my equally small hometown. I was five minutes late on my first day. My mom didn’t wake me up, and when I raged out of my bedroom yelling about my tardiness, she let me know in no uncertain terms that my first real job meant I had to be responsible for myself.

That, as it turned out, was the very first valuable lesson this job would teach me. Over the course of the next year, before I left for college, I picked up lots of good tips and even better life lessons. It is because of the personal growth I experienced during this time that I consider serving one of the best jobs I’ve had to date; here are a few of the invaluable pieces of wisdom I picked up.

Accept being wrong with grace.

It’s hard to admit you’re wrong. It was particularly hard for me, a stubborn 17-year-old girl who had been a camp counselor but never an employee. I made a lot of mistakes in my first days (er, months), but I came away more capable of asking for help and admitting when I didn’t know something.

Be a creative problem solver.

“Yes” is always the answer. Say yes, and then figure it out. Your resources are limited; your time is even more limited. This is true as a server and as a human in general. That shouldn’t stop you from, say, figuring out how to calm a screaming kid who just wants chocolate milk. (You melt a bit of chocolate ice cream and add it to regular milk. I don’t recommend this for home—it’s kind of weak—but it earned me a mighty fine tip from very tired parents.)

When in doubt, ask your server for hidden menu gems.

Servers know the ins and outs of those menus. They know all the odd requests customers have. They know what the cooks make for the staff when you just can’t stomach another patty melt. Ask them what they love—even if it’s not on the menu. You may not have the same taste as them, but it does help you connect a bit. And in the service industry, that can also get you better service.

Everyone has to learn how to be good tippers.

It’s likely the result of where I lived in my younger years (at least, in part), but people are not born good tippers. They rarely understand or know that servers make far below minimum wage and that tips are their primary source of income. I don’t encourage you to make a point of explaining work laws and percentages to your customers, but you do have the power to influence friends and family. Teach them, and the word will spread.

Having the patience of a saint makes life easier.

People are going to be mean. It will happen. But you don’t have to let it turn you, too.

One experience at the restaurant in particular shaped my frame of mind for many future experiences. This gentleman looked grumpy from the moment I saw him climb out of his truck. Indeed, he was sour, and he let me know—his coffee wasn’t hot enough; we didn’t have the jelly he wanted for his biscuit; he doubted we could cook the bacon the way he wanted. I smiled, told him I knew the cook would nail it, and went back with a pot of fresh cup a few minutes later.

As I was taking his “ultra-crisp but not burned and crumbling” bacon to the gentleman, I was inclined to sit it down and just accept he wasn’t going to like me or leave me a tip. I asked him how it looked, and he grumbled. A few minutes later, I circled around to top off his coffee and inquired about the bacon again. “Not bad,” he growled.

He ate in silence—I wasn’t going to bother him because I sensed he didn’t need several check-ins from me—and then he cashed out. “I bet we’ll get the bacon right again the next time you’re here,” I said hesitating. He gave me what I think was probably a smile, at least what he could muster of one and left. I walked away a better person for having handled what could have been a frustrating situation with a bit of grace.

Find your system of mental multitasking.

They say you can’t do more than one thing well at a time, but when table six needs ketchup, table three needs menus, and that table in the back needs more napkins because their kid just spilled spaghetti, you can’t pick just one. Serving and remembering everything your customers ask for, even for a short period of time, requires you to build mini memory programs into your mind. For example (and I still do this today), I built stories to tell myself when I got to the kitchen and needed to gather all the items before returning to the floor. “The kid spilled ketchup all over the menus.” There, in that one sentence, is everything I needed to remember. Does this work for everyone? Probably not. But it has helped me with everything from tests to packing up houses before moving.

Develop money skills—quickly.

This lesson came in two forms—making change quickly at the cash register and learning to budget. Some weekends, I’d make $500 in tips. The next weekend, I might be lucky to leave with $100. Weather, events, and holidays can impact the kind of tips you’re walking out with; you can’t rely on them to be consistent. Because I was in high school, of course, I didn’t have to worry about the important things like a mortgage or bills, but I was responsible for paying for everything I needed my senior year, from graduation trips and prom to football games and my cap and gown. That required me to think ahead and strategize, a practice that’s come in handy over the many years since my last shift at the restaurant.

Don’t underestimate anyone.

I remember this couple clearly. They were dressed simply, nothing fancy or extravagant. She had on a plaid shirt and jeans; he was wearing a pullover golf shirt that had clearly been worn a few times. They both ordered eggs, bacon, and hashbrowns. She wanted hot sauce. I chatted with them each time I’d stop by to see how they were doing. They asked how old I was and what plans I had after high school. I told them about both my summer trip and my plans for college. Their bill total was surely less than $15. My tip was $100. They left me a note, “Go do great things.” I never saw them again, but the lesson of that encounter stuck with me. Treat people equally well because they deserve it, not because you expect something from it.

Build relationships the regulars.

Everyone likes a place where they feel welcomed. We had customers you could expect to see every single weekend, and they knew we were happy to see them when they walked through the door. It might not mean much to you, but they will know your name after a few visits. The same is true today of people you work around but perhaps not directly with. Take the time to learn their names. Everyone appreciates feeling wanted and recognized.

Treat other people with unconditional kindness.

You never know what someone is going through. It’s cliche, but it’s entirely true. Not long before I left my job (it was time to move on to college), I learned that one of the early morning regulars I’d been chatting with every single Saturday for a year was losing his wife to cancer. He’d never mentioned it; my hometown is just really small, and her name ended up on my church’s prayer list. The next weekend, I saw him again and could almost feel the weight on his shoulders. I sat down and said, “Joe, tell me about your beautiful bride. How did you meet?” What ensued was one of the most meaningful conversations I’d ever had in that restaurant. He started at the beginning and brought me to that day, one of the worst she’d had up to that point. She died a few days later. Sometimes, people need a kind heart and listening ear. Be that person whenever you can.